Changes to the Yor's ability?

One of my favorite "tricks" to use playing as the Yor was to sometimes place military starbases with negative speed modules in my territory. The would mean that enemy ships would be stuck at just one movement point per turn as the starbase modules would stack with the Yor's special ability.

Since I just played for the first time in years I tries this but the enemy ships were still moving 3 per turn. Was this changed at some point or did I just not use the correct starbase module?